1. Field of the Invention
The present invention relates to engine starter gearing for an engine and more particularly to engine starter gearing of a positive shift type, including a dentil clutch to provide driving and overrunning features and further including provisions for effecting the automatic separation of the clutch teeth after the engine becomes self-running.
2. Description of the Prior Art
The present invention, like the invention described in my U.S. Pat. No. 4,611,499 is an improvement over the starter gearing system described in U.S. Pat. No. 3,263,509 entitled "Engine Starter Drive" and issued Aug. 2, 1966, to James Digby. The above referenced patent disclosed an engine starter gearing using centrifugal weights and a conical thrust washer for separating dentil clutch teeth after engine start-up to prevent long periods of clutch overrunning and accompanying deleterious wear on the clutch teeth. In Digby, a circular recess is provided in one end of the driven clutch member facing the driving clutch member. An annular thrust washer is fitted in the recess and abuts the driving clutch member. A conical surface is provided on the annular thrust washer facing the driven clutch member. A plurality of centrifugal flyweight members are also provided in the circular recess. The centrifugal flyweight members are provided with an inclined surface cooperating with the conical surface in the annular thrust washer, such that, when an overrunning condition occurs, the centrifugal flyweight members move outwardly and the inclined surface engages the conical surface of the annular thrust washer so as to bias the driving clutch member away from the driven clutch member. The centrifugal flyweight members are prevented from axial or rotational movement by pins extending through suitable bores in the driven clutch member and the centrifugal weight member.
While the engine starter gearing of Digby has been satisfactory in operation, it is difficult and expensive to assemble. This is true because the assembly of the engine starter gearing of Digby was made difficult and expensive by virtue of the fact that the annular thrust washer or thrust ring, the plurality of movable pins and plurality of centrifugal flyweight members must all be somehow maintained in position relative to the driven clutch member during the assembly of the driven clutch member to the driving clutch member.
What is needed, therefore, is an improved engine starter gearing using a centrifugal flyweight clutch separator which is easier and less expensive to assemble and which eliminates the need for an annular thrust washer by combining its function with another element of the engine starter gearing.